Osteonecrosis of the femoral head (ONFH), also known as ischemic necrosis of the femoral head (AVNFH) is a common disease in orthopedics.
In 2006, the Joint Surgery Group of the Orthopaedic Branch of the Chinese Medical Association and the Editorial Department of the Chinese Journal of Orthopaedics organized domestic experts in osteonecrosis to formulate the Expert Recommendations on the Diagnosis and Treatment of Osteonecrosis of the Femoral Head, which to a certain extent standardized the diagnosis, treatment and evaluation methods of osteonecrosis of the femoral head. In March 2012, the Microprosthetics Group of the Orthopaedic Branch of the Chinese Medical Association and the Bone Defects and Osteonecrosis Committee of the Chinese Committee of Restorative and Reconstructive Surgery organized relevant professional experts to discuss, modify and supplement the Expert Recommendations on the Diagnosis and Treatment of Femoral Head Necrosis, and launched the Expert Consensus on the Treatment Standards for Adult Femoral Head Necrosis (2012 Edition).
I. Overview
The definition of osteonecrosis of the femoral head (ONFH) by ARCO and AAOS: ONFH is a disease in which the blood supply to the femoral head is interrupted or damaged, causing the death of bone cells and bone marrow components and their subsequent repair, which then leads to structural changes of the femoral head and collapse of the femoral head, causing joint pain and joint dysfunction, and is a common and intractable disease in the field of orthopedics.
ONFH can be divided into two categories: traumatic and non-traumatic. The former is mainly caused by hip trauma such as femoral neck fracture and hip dislocation, while the latter is mainly caused by corticosteroid application, alcoholism, decompression sickness, sickle cell anemia and idiopathic in China.
Second, the diagnostic criteria
Referring to the diagnostic criteria proposed by the Japanese Ministry of Health and Welfare Osteonecrosis Research Society (JIC) and Mont, the following diagnostic criteria are formulated in China.
1.Clinical symptoms, signs and history Arthralgia mainly in the groin, hip and thigh area, occasionally accompanied by knee pain and limited internal rotation of the hip joint, often with a history of hip trauma, history of corticosteroid application, history of alcoholism and occupational history such as divers.
2.MRI T1WI shows band-like low signal or T2WI shows double line sign.
3.X-ray film changes Common sclerosis, cystic changes and crescentic signs and other appearances.
4.CT scan changes: sclerotic band wrapped around necrotic bone, repaired bone, or subchondral bone fracture.
5.Nuclear bone scan shows perfusion defect (cold area) at the initial stage; necrosis repair stage shows cold area in hot area, i.e. “bagel-like” change.
6.Bone biopsy shows that the bone trabeculae have more than 50% osteocyte vacuolation fossa, and the adjacent multiple trabeculae are involved, and the bone marrow is necrotic.
Expert advice: The diagnosis can be confirmed by meeting two or more criteria. In addition to 1, 2, 3, 4 and 6 can be diagnosed by meeting one of them.
III. Differential diagnosis
Patients with similar clinical symptoms, x-ray changes or MRI changes should be differentiated.
1, intermediate and advanced hip osteoarthritis It may be confused when the joint space is narrowed and subchondral cystic changes appear, but its CT manifestation is sclerosis with cystic changes and MRI changes are mainly low signal, which can be differentiated accordingly.
2, acetabular dysplasia secondary to osteoarthritis The femoral head is not fully wrapped, the joint space is narrowed, disappeared, osteosclerosis, cystic changes, the corresponding area of the acetabulum appears similar changes, easy to distinguish.
3, ankylosing spondylitis involving the hip joint Common in adolescent males, mostly bilateral sacroiliac joint involvement, which is characterized by HLAB27 positive, the femoral head remains round, but the joint space is narrowed, disappeared or even fused, easy to distinguish. Some patients with long-term application of corticosteroids can be combined with ONFH, the femoral head can appear collapsed but often not heavy.
4, rheumatoid arthritis Most commonly seen in women, the head of the femur remains round, but the joint space becomes narrower and disappears. The joint surface of the femoral head and acetabular bone erosion are common and easy to distinguish.
5, chondroblastoma within the femoral head MRI T2WI shows lamellar high signal, CT scan shows irregular osteolytic destruction.
6, Temporary osteoporosis (ITOH) can be seen in middle-aged and young people, is a temporary painful bone marrow edema. x-ray shows reduced bone mass in the femoral head, neck and even rotor. mri shows uniform low signal in T1WI and high signal in T2WI, the range can be up to the femoral neck and rotor, no banded low signal, can be distinguished from ONFH. The lesion can be dissipated within 3-12 months.
7, subchondral incomplete fracture Most commonly seen in elderly patients over 60 years old, without obvious history of trauma, showing sudden onset of hip pain, inability to walk, and limited joint movement. x-ray shows slightly flattening of the upper outer femoral head, T1 and T2-weighted phase of MRI shows subchondral low signal lines, surrounding bone marrow edema, and T2 lipid suppression phase shows lamellar high signal.
8, hyperpigmented villous nodular synovitis Most often occurs in the knee joint, and hip joint involvement is rare. CT and radiographs may show cortical bone erosion of the femoral head, neck or acetabulum, and mild to moderate narrowing of the joint space; MRI shows extensive synovial hypertrophy with a uniform distribution of low or moderate signal.
9, synovial herniation pit This is a benign lesion of synovial tissue proliferation invading the cortex of the femoral neck, MRI T1WI low signal, T2WI high signal small round lesion, located in the upper cortex of the femoral neck, usually asymptomatic.
10, bone infarction Osteonecrosis occurring in the long bone stem has different imaging manifestations at different times, and the MRI manifestations are as follows
①Acute stage: the center of the lesion shows equal or slightly high signal with normal bone marrow in T1WI, high signal in T2WI, and long T1 and long T2 signal at the edge;
(ii) Subacute stage: T1WI of the lesion center is similar to or slightly low signal of normal bone marrow, T2WI is similar to or slightly high signal of normal bone marrow, and long T1 and long T2 signal of the margins;
(3) Chronic stage: low signal in both T1WI and T2WI.
IV. Staging and staging
Once the diagnosis of femoral head necrosis is confirmed, staging should be made to guide the development of a reasonable treatment plan and accurately determine the prognosis. Experts recommend mainly using ARCO staging and Steinberg staging, with reference to Ficat staging. Regarding the staging criteria of femoral head necrosis, domestic experts refer to the aforementioned staging and JIC staging, and put forward improved staging, which can be referred to.
Five, the treatment of femoral head necrosis
There are many treatment methods for femoral head necrosis, and the development of a reasonable treatment plan should take into account the staging, necrosis volume, joint function, as well as the patient’s age, occupation and compliance with joint preservation treatment.
(i) Non-surgical treatment
It is mainly applied to patients with early stage of femoral head necrosis.
1.Protective weight-bearing The use of double crutches can effectively reduce pain, but the use of wheelchairs is not advocated.
2.Medication Non-steroidal anti-inflammatory drugs, low-molecular heparin, alendronate sodium, etc. have certain efficacy, and vasodilator drugs also have certain efficacy.
3.TCM treatment Take the holistic view of Chinese medicine as the guide, follow the basic principles of “combining movement and static, tendons and bones, internal and external treatment, and cooperation between doctors and patients”, emphasize early diagnosis, combination of disease and evidence, and early standardized treatment. For patients in the subclinical stage, Chinese herbal medicines are mainly used to activate blood circulation and resolve blood stasis, supplemented by removing phlegm and dampness, and tonifying kidney and bone, which can promote necrosis repair and prevent or reduce collapse; for femoral head necrosis with pain and other symptoms before collapse, on the basis of protective weight-bearing, Chinese herbal medicines are used to activate blood circulation and resolve blood stasis, promote water and dampness, which can relieve pain and improve joint function; for post-collapse femoral head necrosis, together with surgical repair surgery, can improve surgical effect.
4.Physical therapy includes extracorporeal shock wave, high frequency electric field, hyperbaric oxygen, magnetic therapy, etc., which are beneficial to relieve pain and promote bone repair.
5.Braking and appropriate traction are suitable for ARCO stage I and II cases.
(ii) Surgical treatment
Most ONFH patients will face surgical treatment, which includes two major types of surgery: preserving the patient’s own femoral head and artificial hip joint replacement. Femoral head preservation surgery includes marrow core decompression, bone grafting, osteotomy, etc. It is suitable for patients with ARCO stages I and II and IIIa and IIIb, and ONFH patients with 15% or more of necrosis volume. If the method is appropriate, artificial joint replacement can be avoided or postponed.
1, femoral head medullary core decompression The history of medullary core decompression is long and the efficacy is certain. At present, it can be divided into fine needle drilling decompression and coarse channel medullary decompression.
core decompression. The difference mainly lies in the diameter of the decompression channel, the diameter of the orifice of fine needle drilling decompression is 3mm, 3.5mm or 4mm; the diameter of the orifice of coarse channel medullary decompression is 6mm or more. Experts recommend using a fine needle (about 3mm in diameter) and drilling multiple holes under fluoroscopic guidance. It can be combined with implant material. Core decompression combined with stem cell transplantation (or concentrated autologous bone marrow single nucleus cell transplantation) is currently a Class III medical technology under the control of the Ministry of Health and is not widely performed in China. Based on the good results of clinical application in some domestic units, experts suggest that it should be applied with caution after the establishment of a multicenter long-term follow-up reporting system with large samples.
2.Bone grafting without hemorrhage There are more applications such as trans-femoral rotor decompression bone grafting and trans-femoral head neck bulb decompression bone grafting. Bone grafting methods include compression bone grafting and support bone grafting. The applied bone grafting materials include autologous cancellous bone, allograft bone and bone replacement material.
3.Osteotomy The necrotic area is moved out of the weight-bearing area of the femoral head. The osteotomies used in clinical practice include internal or external osteotomy and transfemoral rotational osteotomy. The principle of osteotomy is to choose not to alter the femoral marrow cavity.
4.Autogenous bone graft with blood transport Autogenous bone graft can be divided into periprosthetic bone flap graft and fibula graft. There are various choices of periprosthetic bone flaps with vascular tips.
① iliac bone (membrane) flap transfer with the ascending branch of the lateral vessels of the rotating femur;
(2) Rotational lateral femoral vessel ascending gluteus medius branch greater trochanteric bone flap transfer;
(iii) Greater trochanteric flap transfer with transverse branch of the spinolateral femoral vessels;
(iv) Iliac (membrane) flap transfer with a deep iliac vessel tip;
⑤ If the entire femoral head or even part of the femoral neck is involved, the femoral head (neck) can be reconstructed by combining the transverse branch greater trochanteric flap with the ascending branch iliac flap;
(6) The rotating medial femoral vascular deep branch greater trochanteric flap and the superior gluteal vascular deep superior branch iliac flap in the posterior approach to the hip joint;
(vii) Bone flap with femoral squared-off tendons (column). The periacetabular bone flap with a vascularized tip is less invasive, more effective, and easy to master, so it is recommended.
In order to increase the strong support in the femoral head, tantalum metal rods can be implanted when applying the periprosthetic hip flap with vascularized tip, which can effectively avoid the postoperative femoral head collapse, and this method has good short-term efficacy, while the long-term efficacy is yet to be determined. The surgical effect of anastomotic vascularized fibular bone graft is also more certain at present. This method is recommended as it is more effective if applied appropriately. The choice of different vascularized bone flaps can be based on their advantages and disadvantages, the operator’s proficiency and other factors.
5.Artificial joint replacement Once the femoral head collapses heavily (ARCO stage IIIc, stage IV), and there is serious loss of joint function or pain, artificial joint replacement should be selected. It is generally believed that the medium- and long-term outcomes of non-cemented or hybrid prostheses are better than cemented prostheses. Arthroplasty for femoral head necrosis is different from arthroplasty for other diseases and some related issues should be noted.
① Patients with long-term corticosteroid application or underlying disease requiring continued treatment, so the infection rate is increased;
②Long-term non-weight bearing, osteoporosis, etc. cause the prosthesis to penetrate into the acetabulum easily;
(③) had performed femoral head preservation surgery, which will bring various technical difficulties;
④ hormonal ONFH, alcoholic ONFH is not only the lesion of the femoral head, its surrounding that is, the whole body bone has also been damaged. Therefore, hormonal ONFH, alcoholic ONFH artificial joint replacement of long-term results, may not be as good as osteoarthritis or traumatic ONFH.
Six, the principles of treatment plan selection
The choice of treatment plan should be based on the stage of necrosis, the patient’s age, the patient’s compliance with joint preservation treatment and other comprehensive considerations.
(A) Treatment options for different stages of femoral head necrosis
For non-traumatic ONFH cases, if the diagnosis is confirmed on one side, the opposite side should be highly suspected, and bilateral MRI examination is recommended.
Treatment of asymptomatic ONFH is recommended for ONFH with large necrotic volume (>30%) and necrosis located in the weight-bearing zone should be treated aggressively and should not wait for symptoms to appear. Combination of medullary core decompression or non-surgical treatment tools is recommended.
ARCO stage I: if it belongs to asymptomatic, non-weight-bearing area, lesion area <15%, it can be closely observed and regularly followed up; those with symptoms or lesions >15% should be actively treated with non-surgical treatment such as lower limb traction and drugs, and also feasible to preserve joint surgical treatment, and medullary core decompression (stem cell transplantation or concentrated autologous bone marrow single nucleus cell transplantation) is recommended.
ARCO stage II: In cases where the femoral head has not yet collapsed, marrow core decompression (stem cell transplantation or concentrated autologous bone marrow single nucleus cell transplantation), autologous bone grafting with hematopoiesis, and bone grafting without hematopoiesis (15% < necrosis < 30%) are recommended.
ARCO stage IIIa, IIIb: various autologous bone grafts with hematopoiesis are recommended.
ARCO stage IIIc, IV: In ONFH cases, if the symptoms are mild and the age is small, joint preservation surgery can be chosen and bone grafting with vascular autologous bone (such as greater trochanteric bone flap with vascular tip combined with iliac bone graft, etc.) is recommended; artificial total hip replacement is recommended for severe femoral head collapse.
Femoral head preservation surgery can often be performed in one or more combinations of several procedures, and a combination of these procedures is recommended, such as medullary core decompression with bone flap grafting. Non-surgical treatment should also be within the scope of comprehensive treatment.
(ii) Age factors and the choice of treatment options
In young and middle-aged ONFH cases, due to the high activity of the patient, a treatment plan that preserves the head and does not adversely affect the possible artificial joint replacement should be chosen. The following are recommended: marrow core decompression (stem cell transplantation), autologous bone graft with hematopoiesis, and bone graft without hematopoiesis (15% < necrosis extent < 30%).
In middle-aged ONFH cases, if in the earlier stages of ONFH (no collapse) should do their best to preserve the head, such as medullary core decompression, bone grafting with or without blood transport; if in the middle and late stages of ONFH, should be combined with the patient’s subjective desire and technical conditions to choose head preservation treatment or artificial arthroplasty. When deciding to perform artificial joint replacement, the preoperative prosthesis selection should fully consider the possibility of secondary revision.
In elderly (>55 years old) ONFH cases, total artificial hip replacement is recommended.
For elderly ONFH cases, it depends on the patient’s original daily activity status, the bone quality of the hip, and the expectation of the longevity of life. It is recommended to perform bipolar (tripolar) artificial femoral head replacement or artificial total hip arthroplasty.
VII. Efficacy evaluation and rehabilitation exercise
The evaluation of the efficacy of ONFH can be divided into clinical evaluation and imaging evaluation. Clinical evaluation adopts hip function score (such as Harris score, WOMAC score, Chinese Medical Association Orthopedic Branch percentage method for efficacy evaluation, etc.), and should be evaluated on a case-by-case basis according to the same stage, similar necrosis area, and the same treatment method. Gait analysis information is also recommended.
Imaging evaluation can be applied to X-ray films with concentric circle templates to observe femoral head shape, joint space and acetabular changes. MRI data should be available for the evaluation of lesions up to stage II. For patients with hemorrhagic bone graft, DSA should be performed and used to evaluate hemorrhagic recovery. Experts recommend the establishment of case files for ONFH patients to accumulate more valuable information, which can help evaluate the efficacy of different etiologies, different necrosis periods, different ages, and different treatment methods, and help reach a consensus on more standardized treatment of ONFH.
Rehabilitation exercise can prevent wasting muscle atrophy in patients with ONFH, and is an effective means to promote early recovery of function. The functional exercise should be mainly active, supplemented by passive, from small to large, from less to more, gradually increasing, and according to the stage of femoral head ischemic necrosis, treatment modality, hip function score and gait analysis data, choose the appropriate exercise method.
(1) Reclining leg lift: lie on your back, lift the affected leg, flex the hip and knee 90°, and repeat the action. 200 times a day in 3 to 4 sessions. Application: conservative treatment of ONFH and post-surgical treatment of bedridden period.
(2) Sitting splitting method: sit on a chair, hands on knees, feet shoulder-width apart, left leg to the left, right leg to the right while fully abducted and adducted. 300 times daily in 3 to 4 sessions. Application: ONFH conservative treatment and surgical treatment can be partially weight-bearing period.
(3) Standing leg lift: hold the fixed object with your hand, keep your body upright, lift the affected leg so that your body is at a right angle to your thigh, bend your hip and knee by 90°, and repeat the action. 300 times daily in 3 to 4 sessions. Apply to: ONFH conservative treatment and surgical treatment can be part of the weight-bearing period.
(4) Squatting method: hold a fixed object with your hands, stand upright with your feet shoulder-width apart, squat and then stand up, and repeat the action. 300 times a day, in 3 to 4 times. Application: ONFH conservative treatment and surgical treatment can be fully weight-bearing period.
(5) Internal rotation and abduction method: hand holding a fixed object, the legs do full internal rotation, abduction and circular movement respectively. 300 times a day, divided into 3 to 4. Apply to: ONFH conservative treatment and surgical treatment can be fully weight-bearing period.
(6) Adhere to the training of walking with crutches or cycling exercise. Apply to: ONFH conservative treatment and surgical treatment can be fully weight-bearing period.